Minimum Flows and Levels (MFLs)

Florida law requires establishment of minimum flows and levels of water bodies to prevent significant harm associated with water withdrawals.

Program overview

Florida law (Chapter 373.042, Florida Statutes) requires the state water management districts or the Department of Environmental Protection to establish minimum flows and levels (MFLs) for aquifers, surface watercourses, and other surface water bodies to identify the limit at which further withdrawals would be significantly harmful to the water resources or ecology of the area. Rivers, streams, estuaries and springs require minimum flows, while minimum levels are developed for lakes, wetlands and aquifers. Minimum flows and levels are adopted into Southwest Florida Water Management District (District) rules (Chapter 40D-8, Florida Administrative Code) and used in the District’s water use permitting program to ensure that withdrawals do not cause significant harm to water resources or the environment.

Water bodies with adopted minimum flows and levels, and those the District is currently or planning to work on, are identified in the District’s Minimum Flows and Levels Priority List and Schedule. The list and schedule, which is updated annually, is based upon the importance of the listed waters to the state or region and the existence of potential for adverse impacts associated with water use.


The District collects and analyzes a variety of data for each water body to help define significant harm and for application of methods that are used to develop minimum flow or level recommendations. An essential component of the District’s minimum flows and levels establishment process includes the voluntary use of peer review in which independent scientists review and comment on proposed minimum flows or levels and the methods used for their derivation. The establishment process also includes an opportunity for public review, which affords all interested stakeholders an opportunity to provide comments prior to incorporation of the flows or levels into District rules. The intent of the process is to be inclusive while developing scientifically defensible minimum flows or levels that will afford protection to the water resources and allow sustainable withdrawals to meet human needs. If actual flows or levels are, or during the next twenty years are expected to be below established minimum flows or levels, the District develops and implements a recovery or prevention strategy (Chapter 40D-80, F.A.C.), in accordance with state law (Chapter 373.0421, Florida Statutes).

Want to know more about minimum flows and levels, visit the Frequently Asked Questions »